vitr tech brief

CCaallddwweellll Marine International, LLC.

Caldwell Marine International, LLC 1433 Highway 34 South, B1 Farmingdale, New Jersey 07727 Tel +1 (732) 557-6100 Fax +1 (732) 341-3078

Caldwell Marine International, LLC (CMI) has recently completed the installation

of 87,500 meters (54.4 miles) of high voltage submarine power cable in British Columbia (BC), Canada. CMI’s sister company Northeast Commonwealth Inc. (NCI) contracted with Mitsubishi International to install the submarine cable plant for the Vancouver Island Transmission Reinforcement (VITR) project. The $295-million VITR project replaces an aging 135 kV transmission cable with a new 600MW-242kV system that will provide Vancouver Island and the Southern Gulf Islands with safe reliable energy that will meet their current and future needs. Overview of the Marine Scope of Work

• Marine Route Survey • Cable Route Engineering • Coordination and Logistics of a Multi-national Project • Extensive Documentation, Reporting, & Quality Management • Transportation of the 6,000+ metric ton Submarine Cable Plant from Japan to BC • Installation of the Cable Plant • Specialized Environmentally Friendly Burial Through eel Grasses

System Overview

The system consists of two submarine crossings (Figures 1 and 2): • Trincomali Channel • Strait of Georgia

Each crossing is comprised of three 242kV, single core fluid filled (SCFF)

submarine power cables.

The Trincomali Channel crossing runs from Montague Terminal (MTG) on the west side of Parker Island across Trincomali Channel to the Maricaibo Terminal (MBO) on the eastern shore of Salt Spring Island, an approximate cable distance of 4.1 km.

The Strait of Georgia crossing starts at the English Bluff Terminal (EBT) in Tsawwassen, BC, and crosses the Strait of Georgia to the Taylor Bay Terminal (TBY) on the eastern shore of Galiano Island, an approximate cable distance of 24.8 km. Approximately 12 km of this segment passes through US waters in Washington State. Of particular interest is the crossing of the “Galiano Ridge” an undersea mountain, which rises from 190m to 50m water depth then down to 150m over a horizontal distance of ~400m. The steep ascent and descent required considerable engineering and site investigations prior to the installation.



Notable Features for the Strait of Georgia Crossing

o Two Canada-US Border Crossings o 190m (620’) Water Depth o 3+ Knots of Current o “Galiano Ridge” Undersea Mountain o 2 km Tidal Flat with Dense Eel Grass Growth o 1m Burial through 2km of Tidal Flats using Specialized Eco Friendly Eel

Grass Burial Tool o 2.1km (128 mton) of Cable Floated During each Initial Landing at EBT o Extensive Environmental Monitoring by Permitting Authorities

Figure 1: Transmission supply route



Fig.2: VITR Transmission Route.

Table 1: Cable designation and length SEGMENT DESIGNATION LENGTH

1 Strait of Georgia - GS1 24,861 meters 2 Strait of Georgia – GS2 24,711 meters 3 Strait of Georgia – GS3 24,828 meters 4 Trincomali Channel – TC4, TC5, TC6 + 300m spare 12,919 meters



Figure 3: Cross Section of Cable

PARAMETER VALUE Overall diameter 143 mm Weight in air 61.1 kg/m Weight in water 44.8 kg/m Minimum inner coiling diameter 16 m Minimum bending radius - sheave 4.0 m Minimum bending radius - gantry 3.0 m Minimum bending radius – final configuration 2.2 m Minimum bending radius – during installation 3.0 m Minimum winding diameter – on drum 3.9 m Maximum sidewall pressure - static 2.0 tonne/m Maximum sidewall pressure - dynamic 3.5 tonne/m Maximum tension 15.7 tonne Allowable twist 7.0/m Bending rigidity 1.5 x 1010 kg/mm2

Table 2: Cable design and handling specifications



Equipment & Methodology Selection

Typically a transmission project of this magnitude is done from a purpose built cable ship. The cable ship would normally load the cable from the factory then transport the cable to the cable grounds and perform the installation. With a cable weight in excess of 6,000 metric tons, very few cable ships can carry 6,000 metric tons in one lot without exceeding the cables mechanical parameters, in particular the relatively low maximum sidewall pressure of the fluid filled cable. Furthermore the initial landing at English Bluff required 2.1 km (6,890’) of cable (128 metric tons) to be floated across environmentally sensitive tidal flats during times of high tides, therefore it is beneficial to have a shallow draft installation vessel for the shore approaches. For these reasons CMI decided to transport the cable plant in the 28,000 dwt handy bulker INDIGO OCEAN (Figure 4), and then install each segment of cable from a shallow draft self propelled DPII Cable Lay Barge (Figure 5). The INDIGO OCEAN served as a floating warehouse; each segment was transferred from the INDIGO OCEAN to the Cable Lay Barge then laid. Cable Plant Transport

The 28,749 DWT Bulk Carrier Indigo Ocean was chartered by NCI for 119 days (Figure 4). She was chosen because the general arrangement of her holds could accommodate three large diameter static cable tanks and the construction was adequate for the concentrated deck loading that the cable plant would place on the tank top (floor of the hold). The Indigo Ocean came on hire on June 9, 2008; she transited from China to Japan, arriving in Port Chiba, Japan on June 13, 2008.

Figure 4: The Indigo Ocean



Cable Lay Barge

NCI Chartered the SEASPAN 201 heavy built deck barge (Figures 5, 6, 7 & 8). The 201 was chosen for her ability to accommodate the large diameter static cable tank, the heavy deck loading of the cable plant, and for her ABS classification. The 201 was outfitted with a 2000 hp, Class II dynamic positioning (DPII) system, and specialized cable handling equipment, some of which has been modified specifically to meet the design parameters of the 242 kV PPLP cable.

• 79.5m x 20m x 5.5m ABS Deck Barge • 2000 hp Class II dynamic positioning system (DP II) • 4 point mooring system • 90 ton rough terrain crane • Two linear cable engines (LCE) • Generators

o Two 400kw for deck machinery/ house power o One for house power

• Overhead gantry with one 3 tonne LBE aloft • Large capacity static cable tank • Mechanized cable coiler • Integrated navigation and cable laying suite • Instrumented overboard chute with strain gauge and cable angle indicator



Figure 5: Cable Lay Barge w/1,600 tonne of cable



Figure 6: Cable Lay Barge



Figure 7: Lay barge layout: starboard side and bow

Figure 8: Lay barge layout: starboard side and stern



Principal Machinery

Cable Handling

Cable Storage

The lay barge was outfitted with a static pipe-stanchion tank capable of holding 25 km of 242 kV PPLP cable. The tank dimensions are:

• Inner diameter: 16 m • Outer diameter: 20.0 m • Sidewall height: 4.5 m • Total deck load: 13.431 tonne/m2

The tank design allowed for the tank to be 94% full when loaded

with GS1, the longest cable of the project.

The 16 meter inner diameter satisfied the minimum inner coiling diameter of the cable. The height of the tank was limited in order to keep the maximum sidewall pressure within the handling specifications. Cable Handling and Tensioning Systems

The primary elements of the cable handling system are the LCE and the instrumented overboard chute. All elements of the cable handling system are designed to keep cable bends to within the allowable specifications. The lay barge is equipped with:

• 1-25 tonne primary LCE (Figure 9) • A backup LCE • An instrumented overboard chute to measure cable tension and

angle (Figure 10) • A 22 m tall gantry with a single Linear Belt Engine (LBE) near

the upper quadrant (Figure 11, & 12) • A mechanized coiling/loading arm (Figure 11)



Linear Cable Engine

The Cable Lay Barge is equipped with two Linear Cable Engines (LCE) the primary LCE (Figure 11) has the following specifications: • Tension capacity: 25 tons • Out-haul speed: 0 – 50 meters/minute • Cable diameter range: 80 mm to 200 mm • Maximum track opening: 350 mm • Maximum hydraulic squeeze: 28 tons • Track length: 6m • Electric over hydraulic control • Electric pump drive

Figure 9: Primary LCE – top view



Overboard Chute

The overboard chute has a 4 meter radius. The chute is equipped with instrumentation to measure tension and cable count. Just beyond the end of the overboard chute an angle sensor rides on the cable (Figure 12). The cable angle sensor, the cable tension load pin, and the cable count sensor output data to the PLOW2008 cable management program. The overboard chute was equipped with two video cameras with remote displays in the navigation/cable management station and the cable control house.

Figure 10 Instrumented overboard chute with angle sensor.



Coiler/Loading System

The coiling system consists primarily of a rotating coiling arm with an adjustable payout trolley through which the cable passes (Figure 11). The arm is designed to fit the specific cable specifications and to work in a 20 meter diameter tank. The coiling arm rotates around a central column on a heavy duty slewing ring and is fitted with a payout trolley that provides the radial positioning of the cable. The trolley position is remotely controlled by an operator, typically located in the tank. The drive system for the coiling arm is capable of matching variable loading speeds from zero to 500 meters/hour.

LBE

Gantry Mechanized Coiling Arm

Static Tank

Thrusters

Figure 11: Cable Lay Barge



Figure 12: LBE on top of gantry

DP II Control System

A dynamic positioning system is a computer controlled propulsion system allowing a vessel to maintain its position in open waters against wind, waves and current. The system consists of computer controlled thrusters whereby the computer calculates and controls the amount and direction of thrust necessary to counteract wind, wave, and current forces in order to prevent or correct deviation from the desired position and heading or course of the vessel. Position reference sensors, combined with wind sensors, current sensors and gyro compasses, provide information to the computer pertaining to the vessel's position and the magnitude and direction of environmental forces affecting its position. The computer program contains a mathematical model of the vessel that includes information pertaining to the wind and current drag of the vessel and the location of the thrusters. This knowledge, combined with the sensor information, allows the computer to calculate the required steering angle and thruster output for each thruster.



The DP control system for the lay barge is a NMS6000 Class II Dynamic Positioning System designed to meet ABS DPS-2 requirements. The NMS6000 uses the latest hardware and software technology to provide a robust and reliable system using common software and hardware platforms to allow integration of shipboard control and monitoring functions into a single user-friendly system. The specific systems that are used to control the Lay Barge consisted of the following components: Main components:

• 2 – DP operator control consoles • 2 – Signal processor units • 1 – Independent backup joystick control system

Peripheral equipment:

• 1 – lot Uninterruptible Power Supplies (UPS) • 2 – UPS power distribution panels • 1 – Portable joystick • 2 – Alarm and event logging printers

Environmental reference sensors:

• 2 – Gyrocompasses • 2 – Vertical reference units • 2 – Wind sensors

Position reference sensors:

• 2 – Trimble Differential Global Positioning System (DGPS) receivers • 1 – Leica DGPS receiver • 1 – Fugro SkyFix receiver •

DP Propulsion System The DP propulsion system consists of four 500 horsepower Thrustmaster thrusters. The thrusters have the following features:

• Fully azimuthing, able to turn through 360° without stops • Individual self-contained diesel-hydraulic power unit (HPU) • Fixed pitch Kaplan propeller in a high-thrust nozzle • Speed controlled by a closed loop hydraulic drive



Cable Loading and Transfer to the Lay Barge Cable Loading at the Factories

Each of the three static cable tanks was erected into a dedicated hold (Figure 14). After being cleared into Japan, NCI’s subcontractor began installation of the 136,080kg (300,000lb) steel cable tank stanchions into the holds of the freight vessel. The stanchions were pre-assembled prior to the arrival of the vessel. Each of the three Strait of Georgia cables (GS1, GS2, and GS3) were coiled into dedicated cable tanks, with the Trincomali channel cable coiled on top of the GS2 cable.

Table 3 illustrates the general loading arrangement of the cable plant. Cable

loading proceeded without incident averaging ~450m/hr. Figure 15 illustrates the cable coiled into the freighter.

Figure 13: The Indigo Ocean



Figure 14: Static Cable Tank

Table 3: The Indigo Ocean loading arrangement

Cable Designation & Length (m)

Tank Dimensions OD x ID x H (m)

Hold #

JPS-GS3, 24,861 21.5x16.0x4.0 2 JPS-GS1, 24,828 21.5x16.0x4.0 3 VISCAS –GS2, 24,711 22.2x16.0x4.8 4 VISCAS –TC, 12,919 22.2x16.0x4.8 4 Ancillary Gear Loose and ISO Containers 1, & 5



Figure 15: Cable loaded in freighter

Transfer to Lay barge

The Trincomali Channel cables were the first to be loaded on the cable lay

barge. The transfer was performed in Cowichan Bay, Vancouver Island; a protected deep water bay with a south east entrance, lying four miles south east of Duncan, BC. The Indigo Ocean was tied alongside the Cowichan Bay Dock at the end of the lumber storage area (Figure 16). During cable transfer the Cable Lay Barge was secured in a T configuration with the stern facing the Indigo Ocean (Figure 17).



Figure16: Cowichan Bay Dock

Figure 17: Cable lay barge and The Indigo Ocean during cable transfer



The cable transfer procedure involved pulling the cable from the tanks

in the hold of the Indigo Ocean and coiling the cable in the cable tank on the lay barge (Figures 18 & 19). The cable was pulled from the tank in the freighter hold using the hydraulically powered 8 meter diameter sheave. The cable came out of the cargo hold, passed over the sheave, and was suspended in a catenary over to the lay barge.

On the lay barge the cable passed through the overboard chute (OBC) then entered the linear cable engine (LCE) which pushed the cable to the top of the gantry (Figures 18 & 19). From the top of the gantry the Liner Belt Engine (LBE) pulled the cable entered into a final 90° quadrant block which guided the cable into the mechanized coiling arm. The coiling arm was used to coil the cable in the tank on the lay barge. All quadrant blocks were designed to keep the cable bend radius within the allowable 3 meter limit. Cable fluid pressure was continuously monitored during the entire transfer process.



8m Power Sheave

Figure 18: Cable transfer to lay barge



Figure 19: Schematic illustration of cable transfer from freight vessel to lay barge



Cable Installation

The cables were planned to be installed in four campaigns, the first operation entailed loading and then laying three cables at Trincomali channel. Due to the length of the Georgia Strait crossing, each segment of the cable was loaded individually then laid, therefore the Georgia Strait cables were installed in three campaigns.

Trincomali Channel

The installations across Trincomali Channel involved an initial landing at the MTG terminal and a final landing at MBO. The crossing of the channel was fairly benign with no major high relief features. There is a rocky area, roughly mid-channel, on TC5. The area was mapped with the ROV and the cable detoured to the east of the route to clear the rocks and avoid suspensions. The following section summarizes the landings and crossing. The initial landing at MTG involved a pull of up to 135 meters from the 20 meter contour to the chase way and an additional 85 - 100 meters up the chase way and in a large curve to the terminal. The cables were floated to shore from the barge to the chase way, and then pulled up the chase way through the terminal to the potheads. At the completion of the pull the cable floats were released and divers positioned the cable on the seafloor.



Figure 20: Float to shore, initial landing at MTG.



Laying operations started with a gradual increase in speed to a maximum of 11–12 meters/minute. Cable payout during the lay was controlled to maintain residual tension between 500 and 1000 kg. The ROV maintained a constant position at the cable touchdown point and the laying operation. On some occasions cable was recovered and re-laid to place the cable in natural gaps between rocky areas.

As the barge approached the final landing at MBO the speed was adjusted to match the arrival time to dawn for the final landing.

Our proprietary PLOW2008 cable monitoring system (Figures 21 & 22) was used to create a model of predicted cable tension, angle, and touchdown point versus bottom depth for each of the Trincomali Channel routes. The PLOW2008 program presents data on a window that shows the maximum and minimum values for cable tension, cable angle, and touchdown distance from the stern of the barge, for the specific distance along the route (KP), as well as the actual measured value of the three parameters. This display was monitored in the wheelhouse, the survey department, DP operators, and the cable engine operator. Payout speed was constantly adjusted to maintain the optimum residual tension on the cable.

The final landing at MBO (Figure 23) involved a pull of approximately 135 meters from the 20 meter contour to the chase way and an additional 85 - 95 meters up the chase way to the terminal.

The cables were floated to shore from the barge to the chase way, then pulled up the chase way through the terminal to the potheads. At the completion of the pull the cable floats were released and the cables positioned on the seafloor by divers.

After the cables were landed, they were positioned and split pipe protection was installed by divers and then the cable was hand jetted to 1m burial (land fall sites only).

After the cables were laid the ROV performed an as laid inspection of all three cables.



Figure 21: Graphical display of PLOW2008 main monitoring screen



Figure 22: Graphical display of PLOW2008 cable monitoring screen

Figure 23: Final landing MBO



Installation – Georgia Strait This section summarizes the procedures used to install the three 25km long cable

segments in the Georgia Strait. The operation was done in three campaigns. EBT landing and pull to terminal:

The landing and pull to the EBT terminal involved a 2.1km float in (128 tonnes of cable) and specialized low impact burial operations. The cable route was designed to minimize the disturbance of eel grasses that grow in the tidal flats, as such there are two ~90˚ turns in the proposed route through the tidal flats The cable routes run parallel to the beach for 2.1 kilometers before turning inshore and an additional 200 meters to the entrance of the tunnel leading up the bluff to the terminal station. The cables required burial through a near shore eel grass zone. The operation required the cable to remain floating for 120hrs. Pre-Landfall Preparations

Pre-landfall preparations included positioning of the Cable Lay Barge in the four point anchor mooring, positioning of the ancillary barges along the route, and pre-trenching at the landing site. The Cable Lay Barge was brought into the mooring under its own power, using the DP system. Synthetic fiber lines were run to each preset anchor and the barge secured in the mooring. The same anchor spread was used for all three landings. The anchors were placed to allow forward movement of the barge in order to maintain the required cable tension as cable was paid out for lead fatigue control. With the Cable Lay Barge in the mooring, the two ancillary barges, the quadrant barge and the EGI barge were positioned. The quadrant barge, served as a turning point for the cable at the last AC before the route turns away from shore. The quadrant barge was positioned with two anchors. One anchor also served as the kedge anchor for the EGI barge on the run parallel to shore. The kedge anchor held the bow of the quadrant barge. An additional smaller anchor was used to “steer” the stern of the barge. The eel Grass Injector (EGI) barge was positioned with the injector blade (Figure 23) at the plow-down position about 200 meters offshore of the landing. This barge was held in position using two spuds.



Figure 23: Low Impact Eel Grass Injector

Prior to each landing an amphibious excavator was used to pre-trench as far along

the trench, from the plow-down position to the HHWL, as tides would allow. Trench spoils were placed on geotextile fabric, as per environmental permit conditions. At the completion of each landing the beach was restored to the original condition to allow recreational use. Cable Landing

The cable was pulled to the EGI barge from the Cable Lay Barge using a 3/4” Dyneema synthetic line run from the EGI barge through the horizontal quadrant on the quadrant barge to the Cable Lay Barge.

Sea Serpent float tubes (Figures 24, 25, & 26) were attached to the cable on the Cable Lay Barge. The cable and floats passed over the stern chute into the water. The float tubes remained secured to the cable as it passed through the turning point at the quadrant barge.



Figure 24: Sea Serpent Float Tube



Quadrant Barge

Figure 25: 2.1km (120 tonnes) of cable floating for 120 hours

When the cable reached the EGI barge the flotation was removed and the cable

brought over the deck of the barge and through the LCE’s on the barge. Pillow floats were attached to the cable for the last 200 meter run to shore. The end of the cable was brought as close as possible to the shore using a workboat. From that point it was attached to the pulling wire for the pull through the tunnel to the pothead.

With the cable end at the pothead, the segment from shore to the EGI barge was positioned using divers and a DGPS system in a workboat. Divers removed the buoys and the cable was situated on the seafloor. The section of cable that was still buoyed by the Sea Serpent system was monitored every few hours by a workboat with a compressor. Sections were topped off with air as required to keep the cable afloat until buried.



Near shore Eelgrass Burial

The cable was buried from the shore to the start of EGI plow burial using either an excavated trench or, where excavation was not feasible, hand jetting by divers. Once the cable was buried from shore to the EGI injector blade, the blade and cable were jetted into the bottom by divers.

The EGI barge was propelled by a hydraulic winch pulling in a 7/8” wire rope that was either attached to a kedge anchor at the AC before the turn offshore or, after that AC was passed, to the port stern anchor on the Cable Lay Barge. The anchor was placed on the bottom and, as the EGI barge pulled on the wire, the position of the anchor was carefully monitored to prevent the Cable Lay Barge moving backwards.

At the completion of the eelgrass burial at the 3 meter contour, the injector blade

was eased to the surface as the barge progressed ahead. The cable was removed from the injector blade and allowed to float toward the barge. A workboat with a DGPS system and divers were used to ensure that the cable was on the route prior to deflation of the flotation system. With the cable laying on the seafloor the cable laying commenced across the Georgia Strait. Georgia Strait Cable Lay

Once the EGI burial operations were completed and the cable unloaded from the injector blade the next phase was the crossing of the Georgia Strait.

The ROV was deployed and the radio links tested for proper operation then the DP system was engaged and the guidance model was allowed to accumulate a history. When the system was stable the soft lines to the anchors were gradually released while careful attention was paid to the movement of the barge and the maintenance of cable tension.

Once the stern of the Cable Lay Barge cleared the offshore anchors the ROV was brought in to monitor the touchdown point and the barge slowly increased the lay speed to match the depth and nature of the seafloor, and the wind and sea conditions. Maximum speed was kept under 15 meters/minute. As the operation approached the Galiano Ridge, lay speed was adjusted to match the time of arrival to the lowest modeled current conditions at the ridge.

NCI’s PLOW2008 cable monitoring system (Figures 21 & 22) was used to create a model of predicted cable tension, angle, and touchdown point versus bottom depth for each of the GS routes.

The PLOW2008 program presents data on a window that shows the maximum and minimum values for cable tension, cable angle, and touchdown distance from the stern of the barge, for the specific distance along the route (KP), as well as the actual measured value of the three parameters. This display was monitored in the wheelhouse by the survey



department, DP operators, and was also used by the cable engine operator. Payout speed was constantly adjusted to maintain the optimum residual tension on the cable. Galiano Ridge Crossing

The Georgia Strait crossing was timed to reach the Galiano Ridge at minimum modeled current conditions. As the Cable Lay Barge approached the ridge the speed was reduced. If a span was seen on the ROV video record, the barge was stopped until the length and nature of the span could be confirmed. The length of the span was measured by counting the helix rings in the suspended section. The rings had previously been measured over specific lengths of cable and a distance per ring calculated.

During the inspection and measurement of the span, the seafloor on either side of

the span was investigated to determine if a detour in the route could be used to avoid or reduce the length of the span. If there was an alternated route, the cable was recovered and reinstalled in the preferred location.

Despite the intensive pre-installation surveys of the ridge and the care taken to

minimize spans the geologic conditions at the ridge made a few long spans unavoidable. Previous studies and discussions resulted in the conclusion that a span greater than 14 meters had the potential for creating vortex induced vibration.

Remediation work to shore up the free span suspension with rock bags is planned for

the summer of 2009 TBY Final Landing and Pull to Beach

Surveys of the landing sites prior to the installation revealed a large boulder field at the entrance cove in Taylor Bay. Prior to the first landing an excavator was used to pre-trench through the boulder field along each of the three cable routes at the TBY landing. Barge Approach, Landing, and Cable Pull Operations – TBY

The final landing at TBY followed the same general procedures for each of the cables. The lay barge approached the landing at dawn and started to rotate to the northwest to orient the final barge heading roughly parallel to the shore. The Cable Lay Barge was stopped offshore of the landing and final cut calculations were made. The cable was cut and sealed and floated off the end of the barge.

The lay barge approached TBY laying cable on DP. As stern of the barge drew past the 20 meter contour the barge started a turn roughly 90° to the proposed route. Pillow floats were attached to the cable. Initially the floats were attached at 2 meter intervals in order to gradually float the cable to the surface and maintain a proper catenary. With the establishment of the catenary, floats were attached at the 1.5 meter interval required to float the cable at the surface. Near the point where the cable started to float at the sea



surface, two woven stoppers were applied to the cable to keep it from floating back toward the touchdown point and these were then anchored to a deadman on shore.

The ROV made a final inspection of the cable installation to the point where the first buoy was attached to the cable.

With the Cable Lay Barge held in position on DP, precise measurements were taken from the overboard chute to the cable termination point. Any required slack was added and a cut length was derived, and the cable was cut and sealed.

The cable float commenced on approval of the final cut length. With workboats standing by to manage the bight and the cable bight secured to the deadman on shore, the Cable Lay Barge started moving to the southeast, parallel to shore, while the cable was pushed off the stern. Flotation, consisting pillow floats and sea serpent sections, was attached to keep the cable at the surface.

When the cut and sealed end of the cable passed off the barge, a workboat was used to bring that end to the chase way. The cable and was attached to the pulling wire using a swivel and the pull up the chase way to the pothead commenced. Burial and Split Pipe Installation – TBY

Prior to split pipe installation the final position of the cable at each landing was verified. A diver walked the cable with a buoy and the buoy was positioned using either DPGS or a laser based Range-Azimuth system.

Split pipe installation followed a standard procedure for each cable. The bottom half of the split pipe was installed under the cable. A distributed temperature sensing (DTS) cable was installed adjacent to the power cable in the pipe. The top sections of split pipe were installed. Finally the split pipe was buried as deep as possible by divers using water jetting.

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